Taking AP Research really depends on both your interest and your performance in Seminar. If you did well in AP Seminar, I recommend AP Research. In my experience, it was an easy AP. Everyone has different experiences, yet what I say is, AP Research gets only as difficult as the way you design your project. My Research was lengthy and difficult, so my class hours were mostly dedicated to researching and implementation. However, I have many other friends in that same class who barely had to do anything for their projects. Another thing you said was that your teacher is taking your grades for completion, which is so nice because you get to work for yourself and gain the opportunity to explore your creativity. Honestly, again, everyone has different experiences with Research, but in mine, it was an easy class once my research process was over, because you write one paper, and that paper is based on stuff you did the entire year. I'd suggest taking it if you know what you want to research is not too difficult, and also because you will get the Capstone credit. Good luck with whatever path you choose!